<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>04_class与style绑定</title>
    <style>
        .aClass {
            color: red;
        }

        .bClass {
            color: blue;

        }

        .cClass {
            font-size: 80px;
        }
    </style>
</head>
<body>
<!--
1. 理解
  在应用界面中, 某个(些)元素的样式是变化的
  class/style绑定就是专门用来实现动态样式效果的技术
2. class绑定: :class='xxx'
  xxx是字符串
  xxx是对象
  xxx是数组
3. style绑定
  :style="{ color: activeColor, fontSize: fontSize + 'px' }"
  其中activeColor/fontSize是data属性
-->
<div id="demo">
    <h2>1. class绑定: :class='xxx'</h2>
    <p v-bind:class="a" class="cClass">xxx是字符串</p>
    <p :class="{aClass:true,bClass:false}">xxx是对象</p>
    <p :class="{aClass:isA,bClass:isB}">xxx是对象</p> <!-- 用的比较多 -->
    <p :class='["aClass","cClass"]'>xxx是数组</p>

    <h2>2. style绑定</h2>
    <p :style="{ color: activeColor, fontSize: fontSize + 'px' }">{ color: activeColor, fontSize: fontSize + 'px' }</p>
    <button @click="update">更新</button>

</div>


<script type="text/javascript" src="../js/vue.js"></script>
<script type="text/javascript">
    const vm = new Vue({
        el: '#demo',
        data: {
            a: 'aClass',
            isA: true,
            isB: false,
            activeColor: 'red',
            fontSize: 100

        },
        methods: {
            update() {
                this.a = 'bClass';
                this.isA = false;
                this.isB = true;
                this.activeColor = 'pink';
                this.fontSize = 10;
            }
        }
    })
    console.log(vm);

</script>
</body>
</html>